article: It is not easy to be a vet  .You never know when you will be called upon to take care of a sick animal. You also do not always know that kind of animal you will be asked to take care of or what you must do to help the sick animal.
  Once, when some children were playing with a dog, they threw a ball into its mouth. The ball got stuck   in the dog's throat   and the dog could not breathe. The dog would die if they did not remove the ball quickly. The dog's owner took the dog to a vet called Robert Smith. Mr. Smith put his hands on the dog's neck. He could feel the ball. He was not sure what to do. He pressed   a little harder. The dog opened its mouth and the ball came flying out! No one was more surprised than Mr. Smith.
  Another vet, peter Brown. Worked with sea animals. One day, he was called upon to take care of a dolphin. The dolphin had something in its mouth that had to be taken out, but it did not want to open its mouth. Nineteen men had to hold the strong and slippery  dolphin so that the vet could open its mouth.
question: How did the ball get into the dog's mouth?
options: Someone pressed it into the dog's mouth. The dog's owner threw it into the dog's mouth. It got into the dog's mouth when the dog was playing with it. Some children threw it into the dog's mouth.